D5800_20 (18) 07-2018
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Switch the instrument on
a minimum of 30 minutes
before running the test to
allow temperature stabilization
of measurement circuitry.
Make sure that the glassware
assembly and the vacuum pump
are cleaned and all the
connections are sealed.
Thoroughly clean
and dry all parts
of the test cup
and its accessories
before starting the test.
Check that the crucible and
cover are free from lacquer.
Stubborn lacquer should be
removed by light abrasion
with fine carborundum powder
on a pad of cotton wool soaked
in solvent or with a fibrous
abrasive pad followed
by a rinse with solvent.
Pass the reamer through each of
the three nozzles in the cover
to ensure that they are clear.
Warning, using a reamer with
a diameter larger than 2
millimeters can
enlarge the nozzles.
This can lead to a
wrong losses result
due to increased airflow.
Run the ball bearing
through the extraction tube
to ensure that it is
clear of contaminants.
Calibrate the vacuum
measuring device
in accordance with the
manufacturer's instructions.
Weigh the empty cup without
its cover to the nearest 0.01
grams.
Weigh into the tiered crucible,
65.0 grams, plus or minus
0.1 grams of reference fluid,
to a precision of 0.01 grams.
This mass is called m sub 1.
Screw on the cover using
the clamp and the spanner.
During this phase, make sure
that the specimen will never
splash on the inside
part of the cover.
If this occurs
even only one time,
the test shall be repeated from
20.3 of the written standard.
Connect the specimen temperature
probe to the instrument.
Press down on the
locking lever located
on the front of
the heating block.
Place the crucible
in the heating block.
Rotate the crucible, securing
the flange under the screw
heads.
Adjust the final position
of the extraction tube
so that it is located in front
of the arm of of the glass y
piece and release
the locking lever.
Connect the extraction tube
to of the glass y piece
and secure the connection
with the clamp.
Be sure that the
stainless extraction
tube, the male connection, and
the right arm of the y piece
are properly aligned.
Start the test by pressing
the On key of the Central
Processing Unit, CPU.
In default configuration,
the printer is activated.
If not, refer to the
instruction manual
to activate the real-time
printing of the specimen
temperature and
the vacuum curves.
When the audible alarm
signals the last three
minutes of the test,
stop the audible alarm
by pressing on the Off key.
Stay in front of
the equipment and be
prepared to disconnect
the extraction tube.
After 60 minutes, the test
is automatically stopped
and the end of the
test alarm sounds.
Remove the specimen
temperature probe.
Disconnect the extraction tube
within 15 seconds, maximum.
Press down the locking lever.
Remove the crucible.
Stop the audible alarm by
pressing on the Off key.
Stand the crucible
in a cold water bath
to a minimum depth
of 30 millimeters.
Check the printed
report to ensure
that the specimen temperature
and vacuum-plotted curves
stayed within the
indicated limits.
Occasionally, the electronics
will generate erroneous noise
spikes in the graph.
These spikes are evident by a
rapid temperature or pressure
excursion followed by a rapid
return to baseline conditions.
These spikes are not cause
for invalidating a test.
If, however, there are
gradual temperature
and/or pressure drifts
or excessive noise spikes
beyond specific limits,
perform the necessary system
maintenance and/or calibrations.
In addition, ensure
the apparatus complies
with the manufacturer's
instruction
and that the procedure
has been adhered to.
After these checks,
rerun the test
from 20.2 of the
written standard.
After 30 minutes, remove the
crucible from the water bath.
Dry the outside and
carefully remove the lid.
This phase is very critical.
Make sure that the
sample is never
in contact with the
inside part of the lid.
It is very important, during the
manipulation of the crucible,
at the start and
end of the test,
to not splash the
internal face of the cover
with the specimen in the cup.
When this occurs, it
leads to higher losses,
and the test must be rerun.
Re-weigh the crucible without
the lid to the nearest 0.01
grams.
Calculate the m sub 2 mass
by subtracting the empty cup
mass from the mass measured in
20.8 of the written standard.
Calculate to the
nearest 0.1%, m over m,
the evaporated loss of
the reference fluid,
using the following equation--
m sub 1 minus m sub 2,
result divided by m sub 1,
then multiplied by 100
where m sub 1 equals
specimen mass before the test.
And m sub 2 equals specimen mass
after the test at 245.2 degrees
Celsius.
Compare the result
obtained against the given
value for the reference fluid.
If the result is within
limits, proceed to section 21
of the written standard.
If the result is not
within the limits,
check that the
apparatus complies
with the manufacturer's
instruction
and that the procedure
has been adhered to.
Recheck the evaporation
loss of the reference oil.
To do so, proceed as described
in 20.2 of the written
standard.